From the very beginning, Zuckerberg made it clear the reason he built TheFacebook.com in his Harvard dorm room and later made it into a real company in California was not to make a boatload of money, but to "make something cool" for users.

And, from 2004 until May 18 of this past year, this "I don't know business stuff"/"I'm content to make something cool" mentality worked for Facebook.

Zuckerberg did make something cool and because of that Facebook gained a huge user base.

As Facebook got bigger, Zuckerberg built an organization that mirrored his own priorities.

He set it up so that there was a super class of hand-picked engineers, developers, and executives working with him on "products" like Messenger or News Feed—and then a subclass of people working on the "ad side" of the business, reporting up to ex-Googler Sheryl Sandberg.

What this meant in terms of results was that while Facebook produced innovative new features for consumers, like an instant messaging product that has wiped out AIM and a News Feed that is slowly destroying portals like AOL.com and Yahoo.com, it meanwhile created ad products that amounted to no more than tiny, small boxes on the far right-hand side of Facebook.com.

Users ignored these ads and marketers hated to pay for them.

Facebook's business suffered because of it. It sprinted to scale because the user numbers compelled marketers to experiment with Facebook.com's poor performing ads, but revenue growth began to decelerate in early 2011.

This structure may seem like an obvious mistake now, but you have to remember that all along, investors provided great incentive for Facebook and Zuckerberg to maintain it. Microsoft made Facebook a $15 billion company in 2007 and Goldman Sachs made it a $50 billion company in 2011.

Also, remember that as Facebook gained massive user adoption, lots of smart people began pegging Facebook to be the next Google.

Google got to be, and continues to be, a $200 billion+ company with senior leadership, in Larry Page and Sergey Brin, that is happy to delegate all revenue concerns to sales guys like Tim Armstrong and MBA types like Nikesh Arora.

Page and Brin also completely ignored monetization for a very long time after they created Google, and this set an example—probably a poor one—for a whole generation of entrepreneurs, including Mark Zuckerberg.

(A better model would be Jeff Bezos, who is equally patient, innovative, and user-focused as the Google guys, but knew he was building a business every step of the way. The Google guys got lucky stumbling upon someone else's idea—search ads, which turned out to the most perfect business in the history of businesses.)

From 2004 to 2012, Zuckerberg made Facebook into a company that made products without any of thought of monetization until later, by some other team.

But then came two icebergs in Facebook's path.

In May 2012, Facebook offered its shares to the public and finally encountered investors who would not reward the company for massive user numbers alone.

At the same time, Facebook's user base began, in surprisingly big numbers, to abandon the traditional way they had always accessed the network, through the ad-supported Facebook.com, for a new one, ad-free Facebook mobile apps.

Facebook's valuation plunged from $100 billion to $50 billion in a matter of weeks.

Zuckerberg, who may not care about money but is extremely competitive and aware that Facebook's low stock price would hurt his ability to recruit great product-makers, got the message.

At his first public appearance since the IPO at the TechCrunch Disrupt conference in September, he explicitly acknowledged this, saying that smart people joined companies like Facebook both because they liked its mission and because they wanted to make "a bunch of money."

And now, to his credit, he changed his own views on product monetization and the way Facebook is organized around it. To his even greater credit, he recognized the shift to mobile as a chance for him to build Facebook again, but with monetization a more central aspect of the the product.

During yesterday's conference call, Zuckerberg announced a big change at Facebook over the past few months.

Teams that once built their products for users only, and left monetization for someone else to worry about later, are now required to build mobile monetization in from the ground up.

"We’re building a lot more integrated ad products now," said Zuckerberg.

"Historically, most of the ad inventory was in this right-hand column. It was a separate experience. We had this ad team and their job was to kind of drive that service, and they could provide that service to every other product team."

"Now, we’ve told every product team that they’re responsible for the advertising experience within each of their products."

Zuckerberg said the first team given these new marching orders is the News Feed team.